Can't open recently downloaded textures: "Cannot read...no such file or directory"
MS Windows includes limitations on the maximum file path to any accessible file - it appears that you have exceeded that limit.

See docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file - in particular the following section :

Maximum Path Length Limitation
In the Windows API (with some exceptions discussed in the following paragraphs), the maximum length for a path is MAX_PATH, which is defined as 260 characters. A local path is structured in the following order: drive letter, colon, backslash, name components separated by backslashes, and a terminating null character. For example, the maximum path on drive D is "D:\some 256-character path string&lt;NUL&gt;" where "&lt;NUL&gt;" represents the invisible terminating null character for the current system codepage.

Your path (including the assumed 'c:\users\' prefix not shown) exceeds the 260 character limit. This means that when Blender (and other programs) attempt to access the files the file is effectively unreadable.

Since this is a limitation of the operating system (rather than a limitation of Blender) the only option is to relocate the files to a more O/S-friendly directory.